U.S. patent application number 17/346036 was filed with the patent office on 2021-12-16 for drug and gene therapy to treat high myopia and other ocular disorders with enlarged eye globes.
The applicant listed for this patent is City University of Hong Kong. Invention is credited to Shuyi MAI, Wenjun XIONG.
Application Number | 20210386714 17/346036 |
Document ID | / |
Family ID | 1000005835306 |
Filed Date | 2021-12-16 |
United States Patent
Application |
20210386714 |
Kind Code |
A1 |
XIONG; Wenjun ; et
al. |
December 16, 2021 |
DRUG AND GENE THERAPY TO TREAT HIGH MYOPIA AND OTHER OCULAR
DISORDERS WITH ENLARGED EYE GLOBES
Abstract
This invention relates to a treatment of various eye conditions
relating to eye enlargement. The conditions can be treated by
inhibiting an upstream protein within the said biological pathway
or by increasing the expression of a downstream receptor within the
same pathway. Inhibition of the upstream protein, sterol regulatory
element binding protein (SREBP), has been achieved using small
molecule inhibitors or nucleic acid in viral vector and increased
expression of the downstream protein, bone morphogenetic protein
(BMP), has been achieved by nucleic acid in viral vector. The
invention relates to the small molecule, nucleic acid and the viral
vector as well as methods of treating the ocular diseases.
Inventors: |
XIONG; Wenjun; (Kowloon,
HK) ; MAI; Shuyi; (Kowloon, HK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
City University of Hong Kong |
Kowloon |
|
HK |
|
|
Family ID: |
1000005835306 |
Appl. No.: |
17/346036 |
Filed: |
June 11, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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63038163 |
Jun 12, 2020 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 31/426 20130101;
A61K 31/21 20130101 |
International
Class: |
A61K 31/426 20060101
A61K031/426; A61K 31/21 20060101 A61K031/21 |
Claims
1. A method of treating, preventing, reversing or delaying onset or
progression of an ocular disorder in a subject in need thereof,
comprising a step of administering to the subject a sterol
regulatory element binding protein (SREBP) inhibitor to the
subject.
2. The method of claim 1, wherein the SREBP inhibitor can inhibit
the activity or suppress the level of SREBP.
3. The method of claim 1, wherein an ocular disorder is
Donnai-Barrow syndrome, Facio-oculo-acoustic-renal syndrome,
Stickler syndrome, inherited high myopia, juvenile-onset myopia,
buphthalmos, or vision loss preferably caused by abnormal eye
enlargement; or the ocular disorder is associated with LRP gene
deficiency, preferably LRP2 gene deficiency; or the ocular disorder
is associated with BMP gene deficiency, preferably BMP2 or BMP4
gene deficiency.
4. The method of claim 1, wherein the SREBP inhibitor is
administered to the subject via topical route, suprachoroidal
injection, subconjunctival route, intravitreal route, retrobulbar
route, intracaemeral route, subretinal route, orally, or
intravenously preferably via subretinal or suprachoroidal injection
route.
5. The method of claim 1, wherein the SREBP inhibitor comprises or
consists of a small molecule chemical, a protein, a nucleic acid,
or a nucleic acid in a vector.
6. The method of claim 5, wherein the small molecule has a
structure of Formula (I) or Formula (II): ##STR00009## wherein
R.sup.1 represents an alkenyl group (optionally a C.sub.2-6 alkenyl
group) substituted with an optionally substituted aryl ring
(preferably a phenyl ring), when the aryl ring is substituted it is
substituted with 1 or 2 halo atoms; R.sup.2 represents an
optionally substituted heteroaryl ring (preferably a pyridyl ring),
when the aryl ring is substituted it is substituted with 1 or 2
alkyl groups (preferably C.sub.1-6 alkyl group); and R.sup.3
represents an alkyl group (optionally a C.sub.1-6 alkyl group).
7. The method of claim 1, wherein the SREBP inhibitor has a
structure of ##STR00010##
8. The method of claim 1, wherein the SREBP inhibitor is a vector
comprising a nucleic acid sequence selected from: SEQ ID NO:1, SEQ
ID NO:2, or a homologue or a functional variant thereof.
9. A method of treating, preventing, reversing or delaying onset or
progression of an ocular disorder in a subject in need thereof,
comprising a step of administering to the subject an agent that can
increase the expression of bone morphogenetic protein 2 (BMP2) or
bone morphogenetic protein 4 (BMP4).
10. The method of claim 9, wherein an ocular disorder is
Donnai-Barrow syndrome, Facio-oculo-acoustic-renal syndrome,
Stickler syndrome, inherited high myopia, juvenile-onset myopia,
buphthalmos, or vision loss preferably caused by abnormal eye
enlargement; or the ocular disorder is associated with LRP gene
deficiency, preferably LRP2 gene deficiency; or the ocular disorder
is associated with BMP gene deficiency, preferably BMP2 or BMP4
gene deficiency.
11. The method of claim 9, wherein the agent is administered to the
subject via topical route, suprachoroidal injection,
subconjunctival route, intravitreal route, retrobulbar route,
intracaemeral route, or subretinal route, preferably via subretinal
route.
12. The method of claim 9, wherein the step of administering
comprises contacting target cells of the subject with the agent,
preferably said cells are Retinal Pigment Epithelium (RPE)
cells.
13. The method of claim 9, wherein the agent comprises or consists
of a small molecule chemical, a protein, a nucleic acid, or a
nucleic acid in a vector.
14. The method of claim 9, wherein the agent comprises or consists
of a nucleic acid sequence encoding BMP2 or a homologue thereof, a
nucleic acid sequence encoding BMP4 or a homologue thereof, a BMP2,
a BMP4, a BMP agonist protein that can activate BMP signalling
pathway, or a combination thereof.
15. A composition for treating an ocular disorder, or controlling
axial growth of an eye of a subject, said composition comprising a)
a SREBP inhibitor that can inhibit the activity or suppress the
expression of a SREBP; b) an agent that can increase the expression
of bone morphogenetic protein 2 (BMP2) or bone morphogenetic
protein 4 (BMP4); and/or c) a vector comprising a Retinal Pigment
Epithelium (RPE) cell-type specific promoter.
16. The composition of claim 15, wherein the vector is an
adeno-associated virus (AAV) vector and the vector comprises a
nucleic acid sequence encoding BMP2 or a homologue thereof, or a
nucleic acid sequence encoding BMP4 or a homologue thereof.
17. The composition of claim 15, wherein the small molecule has a
structure of Formula (I) or Formula (II): ##STR00011## wherein
R.sup.1 represents an alkenyl group (optionally a C.sub.2-6 alkenyl
group) substituted with an optionally substituted aryl ring
(preferably a phenyl ring), when the aryl ring is substituted it is
substituted with 1 or 2 halo atoms; R.sup.2 represents an
optionally substituted heteroaryl ring (preferably a pyridyl ring),
when the aryl ring is substituted it is substituted with 1 or 2
alkyl groups (preferably C.sub.1-6 alkyl group); and R.sup.3
represents an alkyl group (optionally a C.sub.1-6 alkyl group).
18. The composition of claim 15, wherein the SREBP inhibitor has a
structure of ##STR00012##
19. The composition of any claim 15, wherein the SREBP inhibitor
has a nucleic acid sequence comprising: SEQ ID NO:1, SEQ ID NO:2,
or a homologue or a functional variant thereof.
20. The composition of any claim 15, wherein the agent comprises or
consists of a nucleic acid sequence encoding BMP2 or a homologue
thereof, a nucleic acid sequence encoding BMP4 or a homologue
thereof, a BMP2, a BMP4, a BMP agonist protein that can activate
BMP signalling pathway, or a combination thereof.
Description
[0001] This invention relates to a method and compositions for
treatment of various eye conditions relating to eye enlargement.
The conditions can be treated by inhibiting an upstream protein
within a biological pathway or by increasing the expression of a
downstream protein within the same pathway. Inhibition of the
upstream protein, sterol regulatory element binding protein
(SREBP), has been achieved using small molecule inhibitors or
nucleic acid in viral vector and increased expression of the
downstream receptor, bone morphogenetic protein (BMP), has been
achieved by nucleic acid in viral vector. The invention relates to
the small molecule, nucleic acid and the viral vector as well as
methods of treating the ocular diseases.
BACKGROUND
[0002] Myopia, or near-sightedness, a leading cause of visual
impairment, is reaching epidemic proportions in Asia and will
affect half the global population by 2050. Despite this, the
mechanisms regulating postnatal growth of the eye remain poorly
understood.
[0003] The human eye continues to grow and elongate after birth.
Average axial length of newborn babies is 16.8 mm, reaching 23.6 mm
by adulthood. The deviation from the average adult axial length is
quite small, with a standard deviation value of only 0.7 mm.
Postnatal eye growth is most rapid in the first two years, which
then continues at a slower rate through puberty. The control of eye
growth, especially axial length, is of key importance to normal
visual function; uncontrolled eye-growth can result in various
ocular pathologies including high myopia. Although some consider
myopia a simple nuisance, its incidence is dramatically increasing.
The disease already affects 80-90% of young adults in Asia, and
will affect 50% of the global population by 2050. About one billion
will have high myopia, which can lead to complications such as
myopic degeneration and retinal detachment that cause irreversible
vision impairment.
[0004] Despite this urgency, the understanding of the mechanisms of
visually guided eye growth, especially in the context of myopia
development, remains poor. The genetic determinants of GROW and
STOP signals that control eye size independent of visual experience
are relatively understudied. The exact contributions of the many
layers of the eye, from the retina, retinal pigment epithelium
(RPE), choroid to sclera, in controlling and coordinating the
growth of the posterior segment of the eye remains unknown. The
RPE, which is a monolayer of polarized epithelial cells, resides at
a key location between the choroid/sclera and the retina. Besides
its function in maintaining retinal homeostasis, the RPE is also a
major source of growth factors and cytokines, via which it can
signal to and regulate the neighbouring tissues. Thus, the RPE
could play a role in ocular growth regulation.
BRIEF SUMMARY OF THE DISCLOSURE
[0005] In a first aspect, the present invention provides a method
of treating, preventing, reversing or delaying onset or progression
of an ocular disorder in a subject in need thereof, comprising a
step of administering to the subject a sterol regulatory element
binding protein (SREBP) inhibitor.
[0006] Preferably the SREBP inhibitor can inhibit the activity or
suppress the expression of a SREBP. Any potential method to inhibit
SREBP can be used, whether that is gene silencing or small molecule
inhibition or any other conceivable method. Gene silencing can be
achieving by siRNA, shRNA, CRISPR or any other gene editing
technique.
[0007] The invention also contemplates a sterol regulatory element
binding protein (SREBP) inhibitor for use in a method of treating,
preventing, reversing or delaying onset or progression of an ocular
disorder.
[0008] In embodiments the ocular disorder is Donnai-Barrow
syndrome, Facio-oculo-acoutstic-renal syndrome, Stickler syndrome,
inherited high myopia, juvenile-onset myopia, buphthalmos, or
vision loss preferably caused by eye enlargement; or the ocular
disorder is associated with LRP gene deficiency, preferably LRP2
gene deficiency; or the ocular disorder is associated with BMP gene
deficiency, preferably BMP2 or BMP4 gene deficiency.
[0009] The SREBP inhibitor may be administered to the subject via a
topical route, suprachoroidal injection, subconjunctival route,
intravitreal route, retrobulbar route, intracaemeral route,
subretinal route, orally or intravenously, preferably via a
subretinal or suprachoroidal injection route.
[0010] The step of administering to a subject or the route of
administration may comprise contacting target cells of the subject
with the SREBP inhibitor. Preferably said cells are Retinal Pigment
Epithelium (RPE) cells.
[0011] The SREBP inhibitor may comprise or consist of a small
molecule chemical, a protein, a nucleic acid sequence, or a nucleic
acid in a vector.
[0012] The vector may be any vector known to the skilled person.
For example, the vector may be a retrovirus, lentivirus,
adenovirus, adeno-associated virus or a synthetic vector.
Preferably, the vector is an adeno-associated virus.
[0013] The vector may further comprise a component capable of
targeting or driving gene expression in RPE cells. For example, the
vector may further comprise a promoter, which may be human Best1
gene promoter or RPE65 gene promoter.
[0014] In particular, the small molecule is administered orally or
intravenously. The nucleic acid or the nucleic acid in a vector is
preferably administered via a subretinal route or suprachoroidal
route.
[0015] In certain embodiments the SREBP inhibitor is a SREBP
inhibitor capable of inhibiting the expression of SREBP, the
maturation of SREBP, the binding of SREBP to its cofactors, or the
binding of SREBP to a target gene cis regulatory sequence.
[0016] In certain embodiments the SREBP inhibitor is a small
molecule having at least two separated aromatic groups. The small
molecule may optionally comprise a boronate group attached to one
of the aromatic groups or a thiazine group separating the two
aromatic groups. Preferably, the aromatic groups are independently
phenyl or pyridyl.
[0017] In certain embodiments, the SREBP inhibitor is a small
molecule having a structure of Formula (I) or Formula (II):
##STR00001##
wherein R.sup.1 represents an alkenyl group (optionally a C.sub.2-6
alkenyl group) substituted with a substituted or unsubstituted aryl
ring (preferably a phenyl ring); when the aryl ring is substituted,
it is substituted with 1 or 2 halo atoms; R.sup.2 represents a
substituted or unsubstituted heteroaryl ring (preferably a pyridyl
ring); when the heteroaryl ring is substituted, it is substituted
with 1 or 2 alkyl groups (preferably C.sub.1-6 alkyl groups); and
R.sup.3 represents an alkyl group (optionally a C.sub.1-6 alkyl
group).
[0018] R.sup.1 may represent a C.sub.2-6 alkenyl group substituted
with an optionally substituted aryl ring (optionally a phenyl
ring); when the aryl ring is substituted, it is substituted with 1
or 2 halo atoms.
[0019] R.sup.2 may represent a substituted or unsubstituted pyridyl
ring; when the pyridyl ring is substituted it is substituted with 1
or 2 alkyl groups (optionally C.sub.1-6 alkyl groups).
[0020] R.sup.3 may represent a C.sub.1-6 alkyl group.
[0021] Formulae (I) and (II) represent preferred embodiments of the
present invention. However, the present invention also contemplates
compounds having alternative points of substitution to those shown
that are allowed by valency.
[0022] In certain embodiments the small molecule has a structure of
Formula (III):
##STR00002##
wherein R.sup.4 represents an optionally substituted aryl ring
(preferably a phenyl ring), when the aryl ring is substituted it is
substituted with 1 or 2 halo atoms.
[0023] In certain embodiments the small molecule has a structure of
Formula (IV):
##STR00003##
wherein R.sup.5 represents an alkyl group (preferably C.sub.1-6
alkyl group).
[0024] In certain embodiments the small molecule has a structure
selected from:
##STR00004##
[0025] The nucleic acid sequence or the nucleic acid in the vector
may be a small interfering RNA (siRNA), a short hairpin RNA (shRNA)
or CRIPSR all of which are for silencing SREBP.
[0026] The nucleic acid sequence may be: the sequence shown in SEQ
ID NO:1, ID NO:2, or a homologue or a functional variant
thereof.
[0027] The nucleic acid in a vector may be a vector comprising any
of the nucleic acid sequences disclosed herein. For example, the
vector may be AAV-hBest1-Srebp shRNA.
[0028] In a second aspect of the present invention, there is
provided a method of treating, preventing, reversing or delaying
onset or progression of an ocular disorder in a subject in need
thereof, comprising a step of administering to the subject an agent
that can increase the expression of bone morphogenetic protein 2
(BMP2) or bone morphogenetic protein 4 (BMP4).
[0029] The invention also contemplates an agent that can increase
the expression of bone morphogenetic protein 2 (BMP2) or bone
morphogenetic protein 4 (BMP4) for use in a method of treating,
preventing, reversing or delaying onset or progression of an ocular
disorder.
[0030] The ocular disorder may be selected from Donnai-Barrow
syndrome, Facio-oculo-acoustic-renal syndrome, Stickler syndrome,
inherited high myopia, juvenile-onset myopia, buphthalmos, or
vision loss preferably related to eye enlargement; or the ocular
disorder is associated with LRP gene deficiency, preferably LRP2
gene deficiency; or the ocular disorder is associated with BMP2 or
BMP4 gene deficiency.
[0031] The agent may be administered to the subject via a topical
route, suprachoroidal injection, subconjunctival route,
intravitreal route, retrobulbar route, intracameral route, or
subretinal route, preferably via a subretinal or suprachoroidal
route.
[0032] The step of administering or the administration of the agent
may comprise contacting target cells of the subject with the agent,
preferably said cells are Retinal Pigment Epithelium (RPE)
cells.
[0033] In certain embodiments, the agent comprises or consists of a
small molecule chemical, a protein, a nucleic acid, or a nucleic
acid in a vector.
[0034] The agent may comprise or consist of a nucleic acid sequence
encoding BMP2 or a homologue thereof, a nucleic acid sequence
encoding BMP4 or a homologue thereof, a BMP2, a BMP4, a BMP agonist
protein that can activate BMP signalling pathway, or a combination
thereof.
[0035] In a third aspect of the present invention there is provided
a composition for treating an ocular disorder, or controlling axial
growth of an eye of a subject, said composition comprising a) a
SREBP inhibitor that can inhibit the activity or suppress the
expression of a SREBP; b) an agent that can increase the expression
of bone morphogenetic protein 2 (BMP2) or bone morphogenetic
protein 4 (BMP4); and/or c) a vector comprising a Retinal Pigment
Epithelium (RPE) cell-type specific promoter.
[0036] The vector may be an adeno-associated virus (AAV) vector and
the vector comprises a nucleic acid sequence encoding BMP2 or a
homologue thereof, or a nucleic acid sequence encoding BMP4 or a
homologue thereof.
[0037] The SREBP inhibitor may be any small molecule or nucleic
acid sequence disclosed herein. Preferably, the SREBP inhibitor has
a structure of:
##STR00005##
[0038] The SREBP inhibitor may have a nucleic acid sequence
comprising the sequence shown in SEQ ID NO:1, ID NO:2, or a
homologue or a functional variant thereof.
[0039] The agent comprises or consists of a nucleic acid sequence
encoding BMP2 or a homologue thereof, a nucleic acid sequence
encoding BMP4 or a homologue thereof, a BMP2, a BMP4, a BMP agonist
protein that can activate BMP signalling pathway, or a combination
thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Embodiments of the invention are further described by means
of example but not in any limitative sense hereinafter with
reference to the accompanying drawings, in which:
[0041] FIG. 1A is an image of a normal mouse eye from a control
group.
[0042] FIG. 1B is an image of an enlarged mouse eye by Srebp1a
overexpression.
[0043] FIG. 1C is an image of an enlarged mouse eye by Srebp2
overexpression.
[0044] FIG. 1D is an image of an enlarged mouse eye by Lrp2
loss.
[0045] FIG. 1E is an image of an enlarged mouse eye by Bmp2
loss.
[0046] FIG. 1F is an image of a smaller mouse eye by Bmp2
overexpression.
[0047] FIG. 1G is a chart showing mouse eye size (Axial length; ED,
Equatorial Diameter) regulated by Srebp1a and Srebp2.
[0048] FIG. 1H is a chart showing mouse eye size (Axial length; ED,
Equatorial Diameter) regulated by Lrp2 sh1 and Lrp2 sh2.
[0049] FIG. 1I is a chart showing mouse eye size (Axial length; ED,
Equatorial Diameter) regulated by Bmp2.
[0050] FIG. 2A is a chart showing that enlarged mouse eye size
induced by Lrp2 loss can be rescued with Srebp2 shRNA.
[0051] FIG. 2B is a chart showing that Lrp2 gene expression in RPE
is increased by SREBP inhibiting drug BF175.
[0052] FIG. 2C is a chart showing that Lrp2 gene expression in RPE
is increased by SREBP inhibiting drug Fatostatin.
[0053] FIG. 2D is a chart showing that enlarged mouse eye size
induced by Lrp2 loss can be rescued by SREBP inhibiting drug
BF175.
[0054] FIG. 3A shows quantification of axial length (AL) in control
eyes, Lrp2 knockout (ko) eyes, and Lrp2 ko eyes with Bmp2
overexpression. Bmp2 overexpression can effectively prevent AL
increase in Lrp2 ko eyes.
[0055] FIG. 3B shows quantification of retinal thickness in control
eyes, Lrp2 knockout (ko) eyes, and Lrp2 ko eyes with Bmp2
overexpression. Bmp2 overexpression can effectively prevent retinal
thinning in Lrp2 ko eyes.
[0056] FIG. 3C shows biometry measurement with optical coherence
tomography for an uninjected eye.
[0057] FIG. 3D shows biometry measurement with optical coherence
tomography for an eye injected with Lrp2 KO & GFP. Note the
increase of axial length and vitreous chamber depth.
[0058] FIG. 3E shows biometry measurement with optical coherence
tomography for an eye injected with Lrp2 KO & Bmp2. Note the
normal axial length and vitreous chamber depth.
[0059] FIG. 3F shows normal retinal layers of an uninjected control
eye by optical coherence tomography.
[0060] FIG. 3G shows thinner retina of a Lrp2 KO eye injected with
GFP control virus by optical coherence tomography
[0061] FIG. 3H shows normal retinal thickness of a Lrp2 KO eye
injected with Bmp2 virus by optical coherence tomography.
DETAILED DESCRIPTION
[0062] The term "small molecule" is a term recognized in the art.
It is understood to be an organic molecule with a molecular weight
of less than 900 Daltons. Thus, the small molecule of the present
invention may be an organic molecule of less than 900 Daltons.
[0063] The present invention relates to the inhibition of Sterol
Regulatory Element Binding Protein (Srebp2) which is a
transcriptional repressor of the multi-ligand endocytic receptor
Lrp2. The following examples show that Lrp2 deficiency or Srebp
overexpression specifically in the retinal pigment epithelium (RPE)
leads to high myopia in postnatal mice (FIG. 1). Overexpression of
Srebp1a or Srebp2 in the RPE led to eye enlargement (FIG. 1), while
suppression of endogenous Srebp2 prevented eye enlargement induced
by Lrp2 knockdown (FIG. 2). It was further revealed that Bmp2 is
downstream of Srebp-Lrp2. Excessive BMP2 causes microphthalmos,
while insufficient BMP2 led to megalophthalmos (FIG. 1).
RPE-specific overexpression of Bmp2 effectively rescued eye
enlargement and retinal thinning caused by Lrp2 knockout (FIG.
3).
[0064] To separate the functions of Lrp2 in the RPE from other
retinal cells, the phenotypes of RPE-specific Lrp2 knockdown were
examined. Expression of GFP driven by a promoter of the
RPE-specific gene Bestrophin-1 (Best1) could be observed as early
as P1 and was largely restricted to the RPE. Restricting Lrp2
knockdown to the RPE was sufficient to reproduce the significant
eye enlargement phenotype. To further exclude photoreceptor-derived
Lrp2 from any role in initiating the eye enlargement phenotype,
Lrp2 sh1 was specifically expressed in the photoreceptors with an
AAV8 construct using a human rhodopsin kinase (RK) promoter that
drives transgene expression specifically in rods and cones. The
size of eyes between the AAV8-RK-Lrp2 sh1-injected and control
groups were not noticeably different, suggesting that photoreceptor
Lrp2 is not involved in restricting eye growth. These data suggest
that RPE expression of Lrp2 normally functions to restrict neonatal
eyes from excessive growth.
SREBP2 is a Transcriptional Repressor of Lrp2
[0065] SREBP2 acts as a transcriptional repressor of Lrp2, and Lrp2
is negatively regulated by Srebp2. nSrebp2 was selectively
overexpressed in the RPE with an AAV driven by the Best1 promoter.
Eyes injected with AAV8-Best1-nSrebp2 viruses had significantly
increased globe size (FIG. 1). Suppressing Srebp2 expression
rescued the eye enlargement phenotype induced by Lrp2 knockdown.
Knockdown of Srebp2 by shRNA significantly rescued the phenotype
caused by AAV8-Best1-Lrp2 sh1 (FIG. 2). A boron-containing small
molecule BF175, shown below, was tested. In the mouse RPE explant
model, adding BF175 to the culture medium reduced the mRNA level of
Hmgcr and Ldlr, the two known SREBP2 transcriptional targets, while
it significantly increased the mRNA level of Lrp2. The ability of
BF175 to treat eye enlargement induced by Lrp2 knockdown in vivo
was investigated. Co-injection of BF175 effectively suppressed Lrp2
sh1-induced increases in eye size (FIG. 2).
##STR00006##
[0066] Small molecule Fatostatin which is another known inhibitor
of SREBP and currently used in clinical trials to treat cancers
also increases Lrp2 expression in RPE cells, suggesting its
potential to treat high myopia and other eye enlargement
disorders.
##STR00007##
[0067] Bmp2 is downstream of the Srebp2-Lrp2 pathway and that Bmp2
expression is suppressed by Srebp2 while promoted by Lrp2.
[0068] To find out whether BMP2 is the key BMP ligand that controls
postnatal eye size, Bmp2 in mouse RPE was knocked down. Bmp4, Bmp6,
Bmp7 or Bmp11 was also knocked down one by one for comparison, and
two shRNAs with high knockdown efficiency for each gene were
tested. It was found that injection of AAV-Best1-Bmp2 sh1 or sh2
induced the most significant eye enlargement phenotype.
Downregulation of Bmp4, 6, 7 and 11 did not cause any significant
change in eye size. Bmp2 was the key effector downstream of Srebp2
and Lrp2 in regulating eye size and that Bmp2 downregulation was
the cause of eye enlargement. The loss-of-function assay suggested
that BMP2 is a STOP signal of eye growth. Too much BMP2 prevented
the eye globe from reaching a normal size; Bmp2 overexpression in
the RPE led to microphthalmos, with significant decreases in both
AL and ED (FIG. 1).
[0069] In humans, mutations in the LRP2 gene leads to DB/FOAR
syndrome, which is currently untreatable. LRP2 is a large
transmembrane protein with a molecular weight close to 600 kDa.
Known LRP2 mutations are likely loss-of-function mutations,
affecting protein trafficking or stability. Given its large size,
it is difficult to rescue Lrp2 loss-of-function phenotypes by gene
augmentation therapy. Given the data that Bmp2 is downstream of
Lrp2 and that Bmp2 functions to restrict eye growth, it was
hypothesized that increasing Bmp2 expression level could rescue the
ocular phenotypes caused by Lrp2 loss. To test this hypothesis,
Lrp2 conditional knockout mice (Lrp2 cko) was induced by injecting
AAV8-Best1-Cre virus into Lrp2 fl/fl mice. AAV8-Best1-Bmp2 was
co-injected for treatment and eye size was measured by optical
coherence tomography (OCT). Axial length increase in Lrp2 cko mice
was completely rescued by AAV8-Best1-Bmp2 (FIG. 3).
[0070] In highly myopic eyes caused by Lrp2 knockdown, the retinas
were thinner due to the expansion of the posterior eye segment and
the flattening of retina tissue. Retinal thinning was also rescued
by Bmp2 overexpression (FIG. 3). These results suggest that
targeted Bmp2 expression in the RPE is an effective therapeutic
intervention for excessive ocular growth caused by Lrp2 loss.
Materials and Methods
AAV Production
[0071] pAAV, Rep/Cap 2/8, and adenoviral helper plasmids were mixed
with polyethylenimine and added to HEK293T cells. 24 hr after
transfection, cell medium was changed to DMEM only. 72 hr after
transfection, supernatant was collected and cell debris was spun
down and discarded. AAV8 in the supernatant were precipitated by
PEG-8000 (8.5% wt/vol PEG-8000 and 0.4M NaCl for 1.5 hr at 4
degree), centrifuged at 7000.times.g for 10 min, and resuspended in
virus buffer (150 mM NaCl and 20 mM Tris, pH 8.0). The resuspend
was run on an iodixanol gradient, and viruses in 40% fraction were
collected. Recovered AAV virus particles were washed three times
with cold PBS using Amicon 100K columns (EMD Millipore). Protein
gels were run to determine virus titers.
Subretinal Injection of AAV or BF175
[0072] Subretinal injection into P0 (P2 for AAV-RK-viruses) neonate
eyes was performed as known in the art. Approximately 0.25 .mu.l of
viruses in PBS was injected into the subretinal space using a
pulled angled glass pipette controlled by a FemtoJet (Eppendorf).
BF175 stock solution (25 mM in DMSO) was first mixed with Tween-20
(Sigma-Aldrich) at a ratio of 5:1 in order to help BF175 dissolve
in PBS. Then the mixed solution was added to the virus to a final
BF175 concentration of 12.5 uM. The vehicle treatment was virus
added with the same amount of DMSO with Tween-20. For animals used
for qPCR and RNA-seq, both left and right eyes were injected and
used for RNA extraction. For animals used for eye size measurement
or other phenotype characterizations, only the right eye of the
animal was injected, and the fellow left eye was uninjected for
with-in animal controls.
Eye Globe Dimension Measurement
[0073] CD-1 mice were sacrificed at indicated ages. Eyes were
enucleated, and connective tissues and muscles were carefully
removed using tweezers and scissors. Eyes were immersed in PBS in 6
cm petri dish and imaged under a Nikon SMZ800N dissection scope
with 2.times. magnification. ED and AL were measured in imageJ and
converted to millimeters. OCT
[0074] OCT images of mouse eyes were taken using a SD-OCT
(Bioptigen Envisu R4310 SD-OCT, Germany). Detailed procedures can
be found in Supplementary Information
RPE Explant
[0075] Eyes were quickly removed from the euthanized mouse and
dipped in 70% ethanol for decontamination. Under a dissecting
stereomicroscope, connective tissues and muscles were carefully
removed. After washing twice in PBS, eyes were immersed in warm
culture medium (DMEM:F12+10% FBS). Cornea was cutoff using curved
scissors, and lens was pulled out gently with tweezers. Or a
serrate was cut off to remove iris and cornea. Retina and optic
nerve were carefully and completely removed from eye cups. Four
radial cuts were made to enable flat-mounting of eye cups. Each eye
cup was transferred onto the center of a floating polycarbonate
nucleopore filter membrane (Whatman 110406, 0.2 Micron) placed in
6-well plates with the RPE side facing down. The freshly prepared
BF175 stock solution was added to the full culture medium to a
final BF175 concentration of 12.5 uM. Half of the medium was
replaced with fresh medium on the second day. RPE flat-mounts were
harvested at 48 hr in explant and processed for RPE isolation and
RNA extraction.
Mouse RPE Cells Isolation
[0076] Eyecups without retina and optic nerve tissues were
dissected as described in the RPE explant section. Two eyes of the
same mouse were pooled in one tube and processed together. RPE were
incubated in papain solution (Worthington) for 15 minutes. After
washing twice in warm medium, RPE were triturated with 600 .mu.l
pipette tip gently to dissociate the pigmented RPE cells from
sclera. Resuspended cell solution was transferred to a clean tube
and spun down at 600 g.
qPCR
[0077] RNAs were converted to cDNA using PrimeScript RT reagent kit
with gDNA Eraser (Takara). qPCR was performed using PowerUp Sybr
Green Master Mix (Thermofisher) on QuantStudio 3 Real-Time PCR
stems (Applied Biosystems). Gapdh was used as the normalizing
control. qPCR primers were listed in Supplementary Information.
BF175 Synthesis:
##STR00008##
[0079] Preparation of compound 2 A solution of 4-iodotoluene (465
mg, 2.13 mmol) in DMSO (10 mL) was added into a mixture of
1,1'-bis(diphenyl phosphino)ferrocene]dichloropalladium(II)
[PdCl2(dppf)] (78 mg, 0.11 mmol), potassium acetate (KOAc, 0.60 g,
6.11 mmol) and bis(pinacolato) diboron (0.60 g, 2.36 mmol) in a
Schlenk flask under nitrogen. The mixture was stirred at 80.degree.
C. overnight. The crude product was extracted with ethyl acetate
(EtOAc), washed with water, and then dried with MgSO4. The solvent
was evaporated under reduced pressure. The product was purified by
silica gel column chromatography (EtOAc/hexane 1:50) to afford
compound 2 (369 mg, 79%) as a white solid. 1H NMR (400 MHz, CDCl3):
7.73 (d, J=7.2 Hz, 2H), 7.21 (d, J=7.2 Hz, 4H), 2.39 (s, 3H), 1.37
(s, 12H).
[0080] Preparation of compound 3: A mixture of compound 2 (1.53 g,
7.02 mmol), N-bromosuccinimide (NBS, 1.87 g, 10.5 mmol), and
azobisisobutyronitrile (AIBN, 12 mg, 73 mol) in acetonitrile (MeCN,
100 mL) was refluxed at 90.degree. C. for 2 h. After the reaction
was completed, the mixture was allowed to cool at room temperature
and the solvent was removed by rotary evaporation. Hexane was added
to dissolve the product and the remaining solid was removed by
filtration. The filtrate was concentrated and dried in vacuo to
afford the brominated product. The brominated product and
triphenylphosphine (PPh3, 1.68 g, 6.41 mmol) in MeCN (20 mL) was
heated at 90.degree. C. After 12 h, the reaction mixture was cooled
to room temperature, and the solvent was removed under vacuum. The
crude product was then washed with diethyl ether (3.times.5 mL) to
give the desired compound 3 (2.82 g, 72%) as a white solid. 1H NMR
(400 MHz, CDCl3): 7.77-7.67 (m, 9H), 7.64-7.59 (m, 6H), 7.53 (d,
J=7.6 Hz, 2H), 7.03 (dd, J=2.4, 8.4 Hz, 2H), 5.35 (d, J=14.8 Hz,
2H), 1.30 (s, 12H).
[0081] Preparation of compound BF175: A mixture of compound 3 (560
mg, 1.0 mmol) and sodium tert-butoxide (tBuONa, 288 mg, 3.0 mmol)
in DMF (10 mL) was stirred at room temperature under nitrogen for
10 min. To this solution, 3,5-dichlorobenzaldehyde (175 mg, 1.0
mmol) was added and the resulting mixture was stirred at room
temperature for 6 h. The reaction mixture was treated with water
(20 mL) and neutralized with 1 M HCl, then extracted with EtOAc
(3.times.10 mL), washed with brine, and finally dried with MgSO4.
The solvent was evaporated under reduced pressure. The product was
purified by silica gel column chromatography (EtOAc/hexane 1:10) to
afford a mixture of E/Z BF175 (161 mg, 43%) as a white solid. 1H
NMR (400 MHz, CDCl3): 7.82 (d, J=8.0 Hz, 2H), 7.49 (d, J=8.0 Hz,
2H), 7.37 (d, J=2.0 Hz, 2H), 7.24 (t, J=1.6 Hz, 1H), 7.11 (d,
J=16.4 Hz, 1H), 7.01 (d, J=16.4 Hz, 1H), 1.36 (s, 12H).
Sequence CWU 1
1
2159DNAArtificial SequenceSYNTHETIC 1tcttgtcatt gatagaagac
cgttttggcc actgactgac ggtcttctca atgacaaga 59259DNAArtificial
SequenceSYNTHETIC 2tgattgctga caaactgtag cgttttggcc actgactgac
gctacagtgt cagcaatca 59
* * * * *